Staff too busy to resolve my query

I have been doing monthly bloods with lancet for over 20 years and their service was excellent. I did 2 blood tests in Jan 2025 and the incorrect ICD code was entered. These amounts were paid from my savings account. On calling Lancet,they say they took on extra clients and are very busy to resolve my query. This is absolutely unacceptable..they take on more business without getting more staff. So now I have to continue to call them until they find the time to resolve this. It's a shame